Author Question: The two-point calibration for the pH electrode uses two buffers. Which of the following pH val-ues ... (Read 41 times)

Frost2351 · **on:** Jul 16, 2018

The two-point calibration for the pH electrode uses two buffers. Which of the following pH val-ues are correct for these two buffers? 1. 6.839 2. 6.840 3. 7.384 4. 7.495

a. 1 and 3 c. 2 and 4
b. 1 and 4 d. 2 and 3

Question 2

What is responsible for the conversion of glucose to hydrogen peroxide and gluconic acid on the surface of the glucose electrode?

a. Hydrogen peroxide c. Glucagon oxidase
b. Phosphodiesterase d. Glucose oxidase

missalyssa26 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: D
The National Institute of Standards and Technology (NIST) and the International Federation of Clinical Chemistry (IFCC) have established standards for the calibration of blood gas electrodes. A one-point calibration uses a nearly normal pH buffer with a pH of 7.384. A second, lower pH buffer, pH 6.840 is analyzed in the two-point calibration to ensure that the electronic output of the electrode is linear over a wide range of pH levels.

Answer to Question 2

ANS: A
As a blood sample comes in contact with the measuring electrode of the glucose sensor, the glu-cose oxidase on the surface of the electrode converts the glucose in the sample to hydrogen per-oxide and gluconic acid.